Widespread contemporary technologies such as personal computers and the internet mean that users may copy, share, and distribute digital content with ease. Whilst this situation can be of great advantage to end users, it also presents great challenges to those who are reliant on content distribution as a source of income, such as recording artists.
In order to address this problem, previously techniques such as Digital Rights Management (DRM) have been developed, which seek to limit an end user's ability to copy and share digital content. Such techniques have however proved to be unpopular, due to their intrusive nature, and in particular because of the limitations they impose on a given end user to copy content legitimately for personal use (for example making a backup copy of an audio CD). Conversely, once DRM protection on a copy of some digital content has been circumvented, that unprotected and unlicensed copy can be distributed at will by those who choose to do so, meaning that over time such unlicensed copies will tend to proliferate at the expense of the protected copies.
Another approach to digital content distribution is to allow end users to freely copy, share and distribute digital content, and to distribute royalty payments to the providers of that digital content in accordance with its usage. Whilst such a scheme is understandably popular with end users, a drawback is that it is open to abuse by those who seek to distort the royalty payment distribution. For example, by repeatedly downloading an item of digital content which is freely available on the internet, a single user may trick the server providing that digital content into registering much higher usage statistics than are fairly to be attributed to that digital content.
One such example of free digital content distribution is the free internet radio service Last.fm (http://www.last.fm/), which allows users to stream audio content as an internet radio or on-demand service. The frequency with which particular audio tracks are listened to by on-line listeners can be used to determine royalty payments to artists and record labels, yet services such as Last.fm are vulnerable to their statistics being distorted by unscrupulous users.
Accordingly, it would be desirable to provide an improved technique for monitoring content usage, which makes it difficult, if not impossible, to unfairly distort the results of that monitoring, and can therefore provide trusted usage information.